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SPSS SELECT IF – Tutorial & Examples

In SPSS, SELECT IF permanently removes
a selection of cases (rows) from your data.

Summary

SELECT IF in SPSS basically means “delete all cases that don't satisfy one or more conditions”. Like so, select if(gender = 'female'). permanently deletes all cases whose gender is not female. Let's now walk through some real world examples using bank_clean.sav, partly shown below.

SPSS Bank Clean Practice Data

Example 1 - Selection for 1 Variable

Let's first delete all cases who don't have at least a Bachelor's degree. The syntax below:

*Show values and value labels in new output tables.

set tnumbers both.

*Run minimal frequencies table.

frequencies educ.

*Select cases with a Bachelor's degree or higher. Delete all other cases.

select if(educ >= 4).

*Reinspect frequencies.

frequencies educ.

Result

SPSS Select If For 1 Variable Frequencies

As we see, our data now only contain cases having a Bachelor's, Master's or PhD degree. Importantly, cases having

on education level have been removed from the data as well.

Example 2 - Selection for 2 Variables

The syntax below selects cases based on gender and education level: we'll keep only female respondents having at least a Bachelor's degree in our data.

*Inspect contingency table sex and education.

crosstabs educ by gender.

*Select females having a Bachelor's degree or higher.

select if(gender = 0 & educ >= 4).

*Reinspect contingency table.

crosstabs educ by gender.

Result

SPSS Select If For 2 Variables Crosstabs

Example 3 - Selection for (Non) Missing Values

Selections based on (non) missing values are straightforward if you master SPSS Missing Values Functions. For example, the syntax below shows 2 options for deleting cases having fewer than 7 valid values on the last 10 variables (overall to q9).

*Select cases having at least 7 non missing values out of last 10 questions.

select if(nvalid(overall to q9) >= 7)./*At least 7 valid values or at most 3 missings.
execute.

*Alternative way, exact same result.

select if(nmiss(overall to q9) < 4)./*Fewer than 4 missings or more than 6 valid values.
execute.

Tip 1 - Inspect Selection Before Deletion

Before deleting cases, I sometimes want to have a quick look at them. A good way for doing so is creating a FILTER variable. The syntax below shows the right way for doing so.

*Create filter variable holding only zeroes.

compute filt_1 = 0.

*Set filter variable to 1 for cases we want to keep in data.

if(nvalid(overall to q9) >= 7) filt_1 = 1.

*Move unselected cases to bottom of dataset.

sort cases by filt_1 (d).

*Scroll to bottom of dataset now. Note that cases 459 - 464 will be deleted because they have 0 on filt_1.

*If selection as desired, delete other cases.

select if(filt_1).
execute.

Quick note: select if(filt_1). is a shorthand for select if(filt_1 <> 0). and deletes cases having either a zero or a missing value on filt_1.

Result

SPSS Inspect Case Selection Before Deletion Cases that will be deleted are at the bottom of our data. We also readily see we'll have 458 cases left after doing so.

Tip 2 - Use TEMPORARY

A final tip I want to mention is combining SELECT IF with TEMPORARY. By doing so, SELECT IF only applies to the first procedure that follows it. For a quick example, compare the results of the first and second FREQUENCIES commands below.

*Make sure case deletion only applies to first procedure.

temporary.

*Select only female cases.

select if(gender = 0).

*Any procedure now uses only female cases. This also reverses case selection.

frequencies gender educ.

*Rerunning frequencies now uses all cases in data again.

frequencies gender educ.

Final Notes

First off, parentheses around conditions in syntax are not required. Therefore, select if(gender = 0). can also be written as select if gender = 0. I used to think that shorter syntax is always better but I changed my mind over the years. Readability and clear structure are important too. I therefore use (and recommend) parentheses around conditions. This also goes for IF and DO IF.

Right, I guess that should do. Did I miss anything? Please let me know by throwing a comment below.

Thanks for reading!

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